What type of cooling are you using for the AMD FX 8320? Are you using the air cooling that came with it, an aftermarket air cooler or water cooling? You will vary on max stable overclock depending on what you are using to cool the CPU, the CPU itself and the motherboard capabilities.
Also, there is no set instructions for overclocking your CPU. Each CPU will have a different max overclock versus stable overclock. It is a game of trial and error. There are some good guidelines and reccomendations. One that I followed for my AMD FX 6300 was: AMD Bulldozer and Piledriver Overclocking Guide.